You’re the one I’ve been waiting for.
I may be missing it, but is there anything in the sentence to indicate the speaker is a female resulting in the ждала vs. the ждал ending? If not this is more a ‘gotcha’ then grammar based question.
This is one of many sentences where the gender cannot be determined from the non-cloze words in the sentence. However, if you have “Text box size” set to “Changes” rather than “Always the Same”, you can tell that ждал is not long enough and ждала is needed. That’s one of the reasons I set “Text box size” to “Changes” (and “Typing color hint” to “On”).